PGDIR_MASK         18 arch/x86/include/asm/pgtable_32_types.h #define PGDIR_MASK	(~(PGDIR_SIZE - 1))
PGDIR_MASK         54 arch/x86/include/asm/pgtable_64_types.h #define PGDIR_MASK	(~(PGDIR_SIZE - 1))